Heavy-duty vehicles that are commonly used in high-debris environments, such as trucks, tractors, combines, and off-road vehicles, are highly prone to overheating. This is in large part because debris (such as grass, dust, and rocks) can build up and clog the engine's ventilation system, cause coolant leaks, or otherwise result in a dysfunction in engine temperature control. Such vehicles usually have simple temperature gauges (see FIG. 1) to indicate when the engine has reached the “red zone” temperature—i.e., a temperature that is substantially higher than the normal operating temperature (e.g., 50 or more degrees above normal). The conventional temperature gauge 10 of FIG. 1 includes an indicator 20 which can move horizontally to overlap one of three temperature regions: white/blank zone 30, green/yellow zone 40, and red zone 50. Before the vehicle starts/warms up, the indicator is expected to overlap with the white/blank zone 30. Once the vehicle has warmed up and reached its normal operating temperature 60, which often takes around seven minutes, the indicator 20 is expected to overlap with the green/yellow zone 40. When the vehicle has gotten too hot—i.e., reached or exceeded an overheat temperature 70—the indicator is expected to overlap the red zone 50.
However, conventional systems suffer from several drawbacks. For example, damage to the engine begins well before it has reached the “red zone” level of overheating. Also, the operator of the vehicle is often too distracted to notice right away that the gauge indicates temperatures are rising and approaching the red zone 50, and often by the time the operator notices there is overheating, the engine has already suffered costly or even irreparable damage. Moreover, at least for some vehicles, if the engine is allowed to reach temperatures that are considered to be unacceptable according to the conventional temperature gauge 10, the vehicle will become more prone to overheating the next time; for example, the engine will overheat from (for example) a less significant blockage of the ventilation system once it has overheated in the past. What is needed is an early warning system for detecting more relevant increases in temperature and informing the operator of rising temperatures in a more timely and effective manner, before there is overheating and permanent damage.